Simpson Strong-Tie Wood Construction Connectors

Simpson Strong-Tie ® Wood Construction Connectors

DTT Deck Tension Ties

DTT tension ties are safe, cost-effective connectors designed to meet or exceed code requirements for deck construction. These versatile DTT connectors are also load-rated as a holdown for light-duty shearwalls and braced-wall panel applications. For new construction or to make an existing deck code-compliant, the DTT1Z can be used as a tension-tie to satisfy the 2015, 2018 and 2021 IRC provision for a 750 lb. lateral load connection to the house at four locations per deck. This code detail permits the lateral connection from the deck joists to be made to top plates, studs or headers within the supporting structure, which eliminates the need to access to the floor joists inside the home. The DTT1Z is available in a kit (DTT1Z-KT) that includes four DTT1Z connectors, four Strong-Drive ® SDWH Timber-Hex HDG screws (SDWH27800G) and (26) #9 x 1 1/2 " Strong-Drive SD Connector screws. The DTT1Z fastens to the narrow or wide face of a single 2x with Strong-Drive SD Connector screws or nails and accepts a 3⁄8 " bolt, anchor bolt or lag screw (washer required) or can be installed with the Strong-Drive SDWH Timber-Hex HDG screw with an integral washer. The DTT2 can be used to satisfy the IRC provision for a 1,500 lb. lateral load connection at two locations per deck. Additionally, the DTT2 has been tested and evaluated in deck guardrail post applications to resist the code-specified lateral forces at the top of railing assemblies. The DTT2 is also available with longer 2½" Strong-Drive SDS Heavy-Duty Connector screws (model DTT2Z-SDS2.5) to achieve higher loads when needed. The DTT2 fastens easily to the wide face of a single or double 2x using Strong-Drive SDS Heavy-Duty Connector screws (included) and accepts a ½"-diameter bolt or anchor bolt.

1 1 ⁄ 2 "

3 1 ⁄ 4 "

7 1 ⁄

8 "

6 15 ⁄

16 "

4 15 ⁄

16 "

1 5 ⁄ 8 "

1 5 ⁄ 8 "

1 7 ⁄ 16 "

DTT1Z US Patent 10,865,558

DTT2Z US Patent 8,555,580

Floor sheathing nailed at 6" max. on-center to joist with holdown

1 ⁄ 2 " diameter HDG threaded rod with nuts and washers

For guard post installations using Strong-Drive SDWS Timber screws, see technical bulletin T-F-GRDPSTRL. Material: 14 gauge Finish: DTT1Z/DTT2Z — ZMAX ® coating; DTT2SS — stainless steel; see Corrosion Information, pp. 12–15 Installation: • Use all specified fasteners; see General Notes • A standard cut washer (included for DTT2) must be installed between the nut and the seat • Strong-Drive SDS Heavy-Duty Connector screws (SDS) install best with a low-speed high-torque drill with a 3⁄8 " hex head driver (Model BITHEXR38-R1) • Strong-Drive SD Connector screws (SD) install with a 1⁄4 " hex head driver • Strong-Drive SDWH Timber-Hex HDG screws install with a 3⁄8 " hex head driver (Model BITHEXR38-R1) Codes: See p. 11 for Code Reference Key Chart

(6) #9 x 1½" SD screws (shown) or (8) 0.148" x 1½" nails

Continuous flashing (per code), not shown

3 ⁄ 8 " HDG lag screw with HDG washer or SDWH Timber-Hex HDG screw (shown) into top plate, studs, or header

2"

DTT1Z

Floor joist (Solid 2x joist or 2x blocking)

Deck joist

DTT2Z

3" min. thread penetration

Typical DTT1Z Deck-to-House Lateral Load Connection For more information on lateral load connections, see technical bulletin T-C-DECKLAT at strongtie.com

Typical DTT2Z Deck-to-House Lateral Load Connection For more information on lateral load connections, see technical bulletin T-C-DECKLAT at strongtie.com

These products are available with additional corrosion protection. For more information, see p. 14.

For stainless- steel fasteners, see p. 21.

Many of these products are approved for installation with Strong-Drive ® SD Connector screws. See pp. 348–352 for more information.

Decking (typ.)

Allowable Tension Loads

Min. Wood Member Thickness (in.)

Model No.

Fasteners (in.)

Code Ref.

Uses 1 ⁄ 4 " x 1 1 ⁄ 2 " SDS screws (included)

CL Anchor Diameter

DF/SP

SPF/HF

Decks and Fences

4x4 post min.(typ.)

(160)

(160)

(6) #9 x 1 1/2 " SD (6) 0.148 x 1 1/2 (8) 0.148 x 1 1/2

840 910 910

840

2"

3/8 6 or SDWH 3

1 1/2

640 2

DTT1Z

3/4

IBC, FL, LA

850

DTT2Z

C-C-2021 ©2021 SIMPSON STRONG-TIE COMPANY INC.

1,825 2,145 2,145

1,800 1,835

1 1/2

DTT2Z/DTT2SS

(8) 1/4 x 1 1/2 SDS

1 ⁄ 2 " diameter HDG bolts or threaded rods with nuts and washers

13/16

1/2

2x8 min.

3 3

Standard cut washer required between nut and seat (provided)

DTT2Z-SDS2.5 2,105 1. Allowable loads have been increased for wind or earthquake loading with no further increase allowed. Reduce where other loads govern. 2. DTT1Z installations with allowable loads below 750 lb. do not satisfy the 2015/2018/2021 IRC requirements for deck-to-house lateral load connections. 3. The Strong-Drive ® SDWH Timber-Hex HDG screw with a minimum of 3" thread penetration into dry lumber has an allowable withdrawal load (160) of 1,380 lb. into SP, 1225 lb. into DF, and 1,020 lb. into SPF/HF. 4. Load values are valid if the product is flush with the end of the framing member or installed away from the end. 5. The guardrail post illustration above addresses an outward force on the guardrail. An additional DTT2 can be added at the lower bolt to address an inward force. 6. A 3/8 " HDG round washer is required with the use of a lag screw. 7. Fasteners: Nail dimensions are listed diameter by length. SD and SDS screws are Simpson Strong-Tie ® Strong-Drive screws. See pp. 21–22 for fastener information. 13/16 1/2 (8) 1/4 x 2 1/2 SDS

(Simpson Strong-Tie RFB#4x7HDG)

DTT2Z Installed for a Deck Guardrail Post For more information on

guardrail post connections, see technical bulletin T-C-GRDRLPST at strongtie.com

295